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a Grid Computing System - Utopia

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Graphical representation of results:<br />

6. Performance Testing<br />

Analysis of results: What we observed confirms our intuition that when the task size increase<br />

(so the task number decrease), the overhead will decrease. So, by having less tasks, the<br />

network/JavaSpace overhead decrease, so does the exectuion time, to a certain point. After<br />

that point, the execution time begins to increase slightly again.<br />

This is caused by two factors. One is that the number of tasks is not always a multiple of<br />

the number of producers, so there are times (to the end of the application runtime) that some<br />

producers are idle during the life time of the application. The other factor is that not all the<br />

task are of equal size in terms of computational time. Even if the cunks are equal, some tasks<br />

will require more computation than others. If the tasks more computation-intensive will be<br />

taken last (we are using eager scheduling), than again there will be some producers that will<br />

remai idle. This explains the anomaly of increase in execution time to the end of the scale of<br />

tasks number.<br />

6.2.2. Varying the Number of Producers<br />

Objectives: To explore the possible speedup that can be obtained by increasing more producers<br />

and to understand the factors that might limit the speedup.<br />

76

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